Indeed. If it had been a sporadic hardware failure, they would have been exactly as screwed. The fact that they gave an overworked junior dev direct read/write access to the production database is astounding.
Yeah I think him manually clearing a table over and over again was the big problem here. The amount of entropy that had to be introduced into the process to turn a routine task into millions of dollars of loss was tiny. He just needed to click in a slightly different spot on the webpage to bring up USERS instead of RAIDS.